Mass- and isomer-selected S 1 <-S 0 resonant two-photon ionization spectra of the series of supersonically cooled 7-hydroxyquinoline.(H 2 O) n , n=1-4 clusters are reported. These represent a series of hydrogen-bonded w ater-chain clusters, strung between the -O-H group and the N atom of the aromatic molecule. The vibronic spectra of n=2 and 4 clusters are strongly overlapped with the n=3 spectrum, and are identified for the first time; all exhibit large red-shifts (~2000 cm - 1 ). The n=2 and 3 clusters form solely water-chain clusters, while n=4 exists as water-chain clusters and as three other isomers, as shown by UV/UV laser-holeburning.